Most of you probably do this, but there may be some that dont, this only applies to guitar without locking nuts. It still applies to those with locking machine heads.

When you tune your guitar, you sometimes turn the tuner a quarter turn and dont hear any noticeable difference, this is because the string has ‘stuck’ on the nut, a simple way to release the string is to bend the string on the 12th fret, bend the string a full tone and then check the tuning again.
I check my tuning like this all the time, i turn the tune peg / machine head (up or down) and then bend the string on the 12th fret, then check the tuning.

If you have good quality machine heads and a stop tail piece, you should have no need for a locking nut.

I rarely need to retune my guitar after i have tuned up.